Insulated concrete form (ICF) construction techniques typically involve fixing two foam forms a fixed distance apart and pouring concrete between the forms. After the concrete has set, the foam forms remain in place to provide insulation for the concrete structure. Reinforcing members, such as rebar or mesh, may be located in the gap between the forms before the pour to become embedded in the concrete and provide reinforcement to the structure after the concrete sets.
Foam forms for ICF construction typically have ties that hold the two foam layers a set distance apart during the concrete pour. An example of a suitable foam form are Nudura (trademark) forms, though other suitable forms are also commercially available comprising a high enough density and appropriate chemical formula to meet the fire requirements. While the present application only illustrates straight foam forms for straight walls comprising two planar rectangular foam layers for ease of illustration, forms for alternate wall configurations including angles, corners and curves may also similarly be used.
Multi-storey concrete structures have traditionally not been constructed using ICF due to the difficulties in maintaining alignment of the forms during the pour. While ICF is used for construction near ground level, inaccuracies in alignment tend to become exaggerated with each additional storey of construction making their use in multi-storey structures more problematic. Deviations in the forms during the pour require repairs to the foam and concrete structure that are difficult, time consuming and expensive.
One aspect of the difficulties faced in building multi-storey concrete structures using ICF construction techniques has been the lack of ready access to the outside of the structure during construction above the first storey. Another aspect of the difficulties faced in building multi-storey concrete structures using ICF construction techniques has been the difficulty in creating openings through the structure including openings to accommodate windows, doors, sliding doors, glass blocks. A further aspect of the difficulties faced in building multi-storey concrete structures using ICF construction techniques has been creating openings through the structure at upper storey locations where access to the outside of the structure during construction is limited.
Wooden frame openings are a standard residential construction technique used in wood frame residential structures that have been adapted for use in ICF structures. One method of creating openings using ICF construction techniques has been to cut the opening through the forms and create a wooden frame around the shape of the intended opening. After erecting the forms on a suitable base, the permanent wooden frame about the shape of the opening is inserted between the forms. The wooden frame is then braced and concrete poured in at the top of the forms to fill the wall. A waterproof membrane is typically applied over the frame and adjoining area of the forms to prevent moisture from entering the ICF structure. A limitation of this construction technique is that the wooden frame remains in the ICF structure.
An advantage of ICF structures in general is that they are not prone to rot or ingress of water into the structure. The use of a wooden frame may cause complications as wood may react with the concrete, rot over time, or allow ingress of water if the membrane is damaged. A further limitation of using permanent wooden frames is that voids may form in the concrete beneath the frame. A further limitation of using permanent wooden frames is that the portion of the ICF structure bounded by the wooden frame is not thermally sealed compared to the portion of the ICF structure bounded by the insulated forms. A further limitation of using permanent wooden frames is that some building codes restrict the use of wood in contact with concrete for concrete structures.
There is a need for a system and method of ICF construction for creating openings through a multi-storey concrete structure.
There is a further need for a system and method of ICF construction that creates openings through a multi-storey concrete structure without the need for a permanent wooden frame embedded in the structure.